Anodised Aluminium in contact with Mortar

[NalaCap0ne]

Hi Guys/Gals,

I'm currently working on a project which is using a mechanically fixed brick slip facade system called Mechslip (

http://www.ashandlacy.com/construction/products/mechslip/).

The issue that I've come across is that once the bricks are inserted in the rail system, the joints are then filled with mortar. This creates a situation where the mortar is in direct contact with the aluminium rails.

I have brought this up to the system manufacturer, and they informed me that to combat this, they anodize the aluminium rails, and they have provided me with a test report which shows that 24 hours of exposure results in minimal degradation to the anodized coating. I inquired about what happens in the long term, and they ensured me that once the mortar has hardened, it will no longer corrode the aluminium, and even if it is exposed to moisture, the chemical components which cause the corrosion during curing will not leach and affect the aluminium.

I admittedly am no chemist, and I have no idea if what they have told me is true.

My question is, does anyone have experience with LONG TERM corrosion of anodized aluminium exposed to mortar?

Thanks in advance!

Further information:

The mortar is: Parex Historic Mortar (data sheet attached)
Aluminium: AW - 6063 T6

 

[KootK]

I'm no chemist either but I'd think this would be okay. Certainly, anodized aluminum is made to be in permanent contact with concrete on a regular basis.

 

[NalaCap0ne]

That's what I was thinking, but the consultant in me wont let it go without hard evidence! haha.

Thanks for the reply mate.

 

[cvg]

as with any coating, it can be scratched or damaged exposing the uncoated metal which will corrode. sounds like a risky idea. the link below seems to imply that long term corrosion with hardened concrete is a problem.

https://www.concreteconstruction.ne...-does-contact-with-aluminum-affect-concrete_o

 

[OldBldgGuy]

If the anodizing remains intact, there should be no issue. Mill finished aluminum would absolutely be a problem. You have to decide how confident you are in the finish and the absence of damage to it. I was much more sure of these things 35 years ago than I am now, and I've seen enough of my old projects to know that 25 or 30 years really isn't that long in the scheme of things and stuff happens that you didn't think would even matter.

 

[glass99]

It is certainly true that anodized aluminum is used against concrete all the time for curtain walls and their brackets, though it is fairly easy to put in a plastic shim if you have a "problem".